1. Field of the Invention
The present invention relates to the production and use of filaments and use of diamond-coated or diamond filaments, such as fibers, tubes and whiskers.
2. Description of the Prior Art
Small diameter tubes are utilized in many areas of both commerce and research. They are found in biomedical applications as probes and medicinal dispensers, as filtration media in chemical and purification processes, and in such esoteric areas as chaff media for jamming RF frequencies. As described in the parent, copending United States Patent application, entitled DIAMOND-REINFORCED MATRIX COMPOSITES, to Natishan et al., filed May 10, 1991, U.S. Ser. No. 07,698,218, the entirety of which is incorporated herein by reference, diamond and diamond-coated filaments, including diamond and diamond-coated fibers, tubes and whiskers are also useful as reinforcement materials for composites, including, but not limited to thermal management materials. In all of these areas, research continues in an effort to develop tubules or fibers with enhanced properties (increased hardness, lower chemical reactivity, increased thermal conductivity, etc.).
Diamond is inert in a variety of environments including inorganic acids, bases and organic solvents, including solutions such as hot aqua-regia (2/3 HCl and 1/3 HNO.sub.3), hot aqua-fortis (2/3 H.sub.2 SO.sub.4 and 1/3 HNO.sub.3) and hot caustic solutions (KOH). Additionally, diamond has a very high thermal conductivity (a factor of 5 greater than copper), it is an electrical insulator which can be doped to become a semi-conductor, it has an excellent resistance to wear, and it has a frictional co-efficient similar to that of Teflon.TM.. These materials properties provide many opportunities for use in the areas described above.